scholarly journals Incipient sliding of adhesive contacts

Friction ◽  
2021 ◽  
Author(s):  
Francesc Pérez-Ràfols ◽  
Lucia Nicola
Keyword(s):  
Contact Pressure ◽  
Tangential Direction ◽  
Tangential Displacement ◽  
Smooth Cylinder ◽  
Pressure Spike ◽  
Adhesive Contacts ◽  
Adhesion Friction

AbstractA model is proposed herein to investigate the incipient sliding of contacts in the presence of both friction and adhesion, where the interfacial response is modeled based on traction-separation laws. A Maugis-like parameter is defined to characterize the response in the tangential direction. Subsequently, the model is used to investigate the contact between a smooth cylinder and a flat body, where adhesion-friction interactions are strong. A range of behaviors are observed when a tangential displacement is imposed: When the parameter is low, the contact pressure exhibits a relatively constant profile; when it is high, a pressure spike is observed at the edge of the contact. This difference is caused by a significant interface compliance in the former case, which limits the amount of slip. The results for the mid-range values of the Maugis-like parameter can qualitatively replicate various experiments performed using polydimethylsiloxane (PDMS) balls.

Study of a Major Mechanism for Self-Loosening of Bolted Joints

2006 ◽  
Author(s):  
Ziqin Wang ◽  
Yanyao Jiang
Keyword(s):  
Contact Pressure ◽  
Three Dimensional ◽  
Bending Moment ◽  
Tangential Direction ◽  
Relative Displacement ◽  
Bolted Joints ◽  
Major Mechanism ◽  
Fe Simulations ◽  
Local Slip ◽  
D Model

A recent three-dimensional (3-D) finite element (FE) investigation on self-loosening of bolted joints revealed that two major mechanisms were responsible for the second-stage (nut rotation) self-loosening of bolted joints. One of the mechanisms is the slip-stick contact of the thread surfaces under the combined contact pressure and reversed bending moment exerted from the reversed transverse loading. The current investigation is a detailed study of the slip-stick contact of the thread surfaces with models that mimic the bolt loading condition. The contact pressure and the reversed bending moment are obtained from an earlier simulation for an M12 bolt. The FE simulations indicate that, with the contact pressure on the thread surface of the bolt and nut, the alternating bending moment results in the gradual motion between the contact thread surfaces. A detailed look at the contact surfaces reveals that localized slip along the tangential direction occurs in part of the contact area and the accumulation of this local slip is responsible for the gradual relative motion between bolt and nut. The FE simulations also indicate that the amplitude of the bending moment greatly influences the relative displacement between the bolt and the nut. There exists a threshold below which local slip will not occur. Results from a two-dimensional (2-D) model are discussed and compared with those obtained from a 3-D model.

scholarly journals ANALYSIS OF THE UNILATERAL CONTACT PROBLEM FOR BIPHASIC CARTILAGE LAYERS WITH AN ELLIPTIC CONTACT ZONE AND ACCOUNTING FOR TANGENTIAL DISPLACEMENTS

2016 ◽  
Vol 21 (5) ◽  
pp. 585-609 ◽  
Author(s):  
Sergei Rogosin ◽  
Gennady Mishuris ◽  
Anna Koroleva ◽  
Anastasiya Vinakurava
Keyword(s):  
Contact Problem ◽  
Contact Pressure ◽  
Contact Zone ◽  
Order Approximation ◽  
Three Dimensional ◽  
Approximation Problem ◽  
Unilateral Contact ◽  
Tangential Displacement ◽  
Good Convergence ◽  
Integral Characteristics

A three-dimensional unilateral contact problem for articular cartilage layers attached to subchondral bones shaped as elliptic paraboloids is considered in the framework of the biphasic cartilage model. The main novelty of the study is in accounting not only for the normal (vertical), but also for tangential vertical (horizontal) displacements of the contacting surfaces. Exact general relationships have been established between the contact approach and some integral characteristics of the contact pressure, including the contact force. Asymptotic representations for the contact pressure integral characteristics are obtained in terms of the contact approach and some integral characteristics of the contact zone. The main result is represented by the first-order approximation problem. We supply the theoretical description of the asymptotic method by numerical analysis of the model. Our calculations demonstrate good convergence of the numerical scheme in determination of the parameters. In particular, it is shown that accounting for the tangential displacement is important in cases where the contact zone is non-circular.

Elastic deflection of the sliding bearing interface in the tangential direction

2002 ◽  
Vol 216 (2) ◽  
pp. 235-242
Author(s):  
J Ni ◽  
Z Zhu
Keyword(s):  
Linear Relationship ◽  
Elastic Deformation ◽  
Machine Tools ◽  
Tangential Force ◽  
Tangential Direction ◽  
Tangential Displacement ◽  
Sliding Bearing ◽  
Elastic Deflection ◽  
Linear Elastic ◽  
Elastic Characteristics

The elastic deflection of the sliding bearing interface of machine tools in the tangential direction is important for ultraprecision positioning applications. This study focuses on investigating the magnitude of such tangential elastic deflection through experiments. A nanoprecison linear piezomotor is used to apply tangential force, and capacitance sensors of submicron resolution are used to measure displacements. Experimental results show that the bearing interface features linear elastic characteristics in the tangential direction when the range of tangential displacements is less than 50 nm. When the range is larger than 50nm, the interface only retains a certain amount of tangential deflection in an unloading cycle. The tangential force has a linear relationship with the tangential displacement only in the stage of elastic deformation which is submicron in magnitude.

scholarly journals Influence of tangential displacement on the adhesion strength of a contact between a parabolic profile and an elastic half-space

2017 ◽  
Vol 4 (8) ◽  
pp. 161010 ◽  
Author(s):  
Valentin L. Popov ◽  
Iakov A. Lyashenko ◽  
Alexander E. Filippov
Keyword(s):  
Half Space ◽  
Adhesion Strength ◽  
Adhesion Force ◽  
Tangential Force ◽  
Elastic Half Space ◽  
Tangential Displacement ◽  
Bodies Of Revolution ◽  
Parabolic Profile ◽  
Rotationally Symmetric ◽  
Adhesive Contacts

The adhesion strength of a contact between a rotationally symmetric indenter and an elastic half-space is analysed analytically and numerically using an extension of the method of dimensionality reduction for superimposed normal/tangential adhesive contacts. In particular, the dependence of the critical adhesion force on the simultaneously applied tangential force is obtained and the relevant dimensionless parameters of the problem are identified. The fracture criterion used coincides with that suggested by Johnson. In this paper, it is used to develop a method that is applicable straightforwardly to adhesive contacts of arbitrary bodies of revolution with compact contact area.

scholarly journals Influence of Tangential Displacement on the Adhesion Force between Gradient Materials

2020 ◽  
Vol 65 (3) ◽  
pp. 205
Author(s):  
I. A. Lyashenko ◽  
Z. M. Liashenko
Keyword(s):  
Normal Force ◽  
Adhesion Force ◽  
Tangential Force ◽  
Adhesive Contact ◽  
Critical Force ◽  
Tangential Displacement ◽  
Optimal Parameters ◽  
Gradient Materials ◽  
Force Components ◽  
Adhesive Contacts

The influence of a tangential displacement on the strength of the adhesive contacts between gradient materials with different gradings of their properties has been studied. Variants with a controlled force (fixed load) and a controlled displacement (fixed grips) are considered. A relationship between the normal and tangential critical force components at which the contact is destroyed is obtained. It is valid within the whole interval of the gradient parameters, where the detachment criterium is obeyed. The optimal parameters at which the adhesive contact strength is maximum are determined. A case of detachment under the action of only the tangential force, i.e. when the normal force equals zero, is analyzed separately.

Contact Stress Analysis During Fretting of a Surface Modified Flat-on-Flat With Round Edge

2019 ◽  
Author(s):  
Pankaj Dhaka ◽  
Raghu V. Prakash
Keyword(s):  
Elastic Modulus ◽  
Yield Strength ◽  
Tensile Stress ◽  
Surface Treatment ◽  
Contact Pressure ◽  
Normal Load ◽  
Contact Geometry ◽  
Parent Material ◽  
Tangential Displacement ◽  
Element Analysis

Abstract In the present work, a two-dimensional finite element analysis is carried out to understand the influence of contact geometry and surface treatment on the fretting behavior of a flat with round edge-on-flat plate contact. The fretting pad and plate are modeled using isotropic elastic material properties of Ti-6Al-4V. The mating pair was subjected to a constant normal load followed by a tangential displacement. The effect of contact geometry was studied by independently varying length of the central flat region and radii of corners. Parameters important from the context of fretting viz. contact pressure and normal stress (in tangential direction) were extracted. The effect of surface treatment was studied by modeling two layers of different elastic modulus and yield strength on the mating surfaces. It is found that addition of intermediate layers of lower elastic modulus and yield strength than the parent material leads to a reduction in both contact pressure and peak tensile stress; the influence was more on the peak tensile stress than contact pressure. Further, the addition of softer and less stiff layers on the pad is noted to be less advantageous than adding it on both pad and substrate or substrate only case. The study suggests that contact geometry should be taken into account while carrying out surface modifications of contact pairs.

Spherical Elastic–Plastic Contact Model for Power-Law Hardening Materials Under Combined Normal and Tangential Loads

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Bin Zhao ◽  
Song Zhang ◽  
Leon M. Keer
Keyword(s):  
Contact Pressure ◽  
Power Law ◽  
Contact Area ◽  
Normal Force ◽  
Tangential Force ◽  
Tangential Displacement ◽  
Tangential Load ◽  
Elastic Plastic ◽  
Normal And Tangential Loads ◽  
Von Mises

The contact between a power-law hardening elastic–plastic sphere and a rigid flat under combined normal and tangential loads in full stick is studied in this work. The displacement-driven loading is used since the frictional contact problems under the displacement-driven loading are widespread in the fields of metal forming and orthogonal cutting. The loading process is as follows: First, a normal displacement-driven loading is imposed on the rigid flat and kept constant; then, an additional tangential displacement-driven loading is applied to the rigid flat. The elastic–plastic contact behavior in presliding is investigated with a proposed finite element (FE) model, including the tangential force, the von Mises stress, the normal force, the contact pressure, and the contact area. The effect of the strain-hardening exponent on contact behavior is considered. It is seen that the tangential force increases nonlinearly with the increase of the tangential displacement, exhibiting gradual stiffness reduction which implies that the junction becomes more plastic. The von Mises stresses moves along the direction of the tangential load, while the maximum stress moves to the contact surface from the below. The normal force diminishes as the tangential load increases, and more obviously for the lower hardening exponent cases. The contact pressure also decreases more significantly for the lower hardening exponent cases. In addition, smaller exponents result in a greater increase of the contact area. The empirical expressions of the tangential force and the contact area in the tangential loading process are also proposed by fitting to the FE results.

Maximum Interlabial Pressures in Normal Speakers

1997 ◽  
Vol 40 (2) ◽  
pp. 400-404 ◽  
Author(s):  
Virginia A. Hinton ◽  
Winston M. C. Arokiasamy
Keyword(s):  
Speech Production ◽  
Contact Pressure ◽  
Direct Evidence ◽  
Unit Area ◽  
Jaw Movement ◽  
Contractile Forces ◽  
Contact Pressures ◽  
Muscle Contractile

It has been hypothesized that typical speech movements do not involve large muscular forces and that normal speakers use less than 20% of the maximum orofacial muscle contractile forces that are available (e.g., Amerman, 1993; Barlow & Abbs, 1984; Barlow & Netsell, 1986; DePaul & Brooks, 1993). However, no direct evidence for this hypothesis has been provided. This study investigated the percentage of maximum interlabial contact pressures (force per unit area) typically used during speech production. The primary conclusion of this study is that normal speakers typically use less than 20% of the available interlabial contact pressure, whether or not the jaw contributes to bilabial closure. Production of the phone [p] at conversational rate and intensity generated an average of 10.56% of maximum available interlabial pressure (MILP) when jaw movement was not restricted and 14.62% when jaw movement was eliminated.

Rim Slip and Bead Fitment of Tires: Analysis and Design2

2006 ◽  
Vol 34 (1) ◽  
pp. 38-63 ◽  
Author(s):  
C. Lee
Keyword(s):  
Pressure Distribution ◽  
Contact Pressure ◽  
Frictional Torque ◽  
Finite Element Analyses ◽  
Inflation Pressure ◽  
Contact Pressure Distribution ◽  
Design Modification ◽  
Iterative Design ◽  
Slip Resistance ◽  
Braking Torque

Abstract A tire slips circumferentially on the rim when subjected to a driving or braking torque greater than the maximum tire-rim frictional torque. The balance of the tire-rim assembly achieved with weight attachment at certain circumferential locations in tire mounting is then lost, and vibration or adverse effects on handling may result when the tire is rolled. Bead fitment refers to the fit between a tire and its rim, and in particular, to whether a gap exists between the two. Rim slip resistance, or the maximum tire-rim frictional torque, is the integral of the product of contact pressure, friction coefficient, and the distance to the wheel center over the entire tire-rim interface. Analytical solutions and finite element analyses were used to study the dependence of the contact pressure distribution on tire design and operating attributes such as mold ring profile, bead bundle construction and diameter, and inflation pressure, etc. The tire-rim contact pressure distribution consists of two parts. The pressure on the ledge and the flange, respectively, comes primarily from tire-rim interference and inflation. Relative contributions of the two to the total rim slip resistance vary with tire types, depending on the magnitudes of ledge interference and inflation pressure. Based on the analyses, general guidelines are established for bead design modification to improve rim slip resistance and mountability, and to reduce the sensitivity to manufacturing variability. An iterative design and analysis procedure is also developed to improve bead fitment.

Finite Element Simulation of Tire-Rim Interface

1989 ◽  
Vol 17 (4) ◽  
pp. 305-325 ◽  
Author(s):  
N. T. Tseng ◽  
R. G. Pelle ◽  
J. P. Chang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Finite Element Simulation ◽  
Contact Pressure ◽  
Element Model ◽  
Experimental Measurements ◽  
Inflation Pressure ◽  
Interference Fit ◽  
Element Simulation ◽  
Rubber Composite

Abstract A finite element model was developed to simulate the tire-rim interface. Elastomers were modeled by nonlinear incompressible elements, whereas plies were simulated by cord-rubber composite elements. Gap elements were used to simulate the opening between tire and rim at zero inflation pressure. This opening closed when the inflation pressure was increased gradually. The predicted distribution of contact pressure at the tire-rim interface agreed very well with the available experimental measurements. Several variations of the tire-rim interference fit were analyzed.

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